Federation

Federation is the joining of one user’s fabric to another user’s fabric. A household sharing a family layer, an organisation onboarding members, a guild forming around a shared interest — each is a federation between fabrics.

Federation is distinct from cross-machine reach. Cross-machine is one user’s fabric stretching across that user’s own devices; federation crosses to another user’s devices. The two have different identity stories (who-is-who across fabrics), different trust postures (what each party may see), and different deployment shapes.

The user-facing surfaces for federation are still being built. See Cross-machine for the practical line between the two concepts today.